With development of intelligent terminal technologies, intelligent terminals with touchscreen technologies are the mainstream of the current market, and a user can operate an intelligent terminal only by operating on a touchscreen, thereby greatly improving convenience and experience of user operations.
Currently, a touchscreen is generally a capacitive touch panel (CTP) and is applicable to multi-touch, that is, a touchscreen can identify touch points simultaneously touched by different conductors on the touchscreen.
However, although a touchscreen is applicable to multi-touch, there is an upper limit to touch points that can be identified by the touchscreen. For example, a touchscreen can simultaneously identify only touch points of three different conductors, for example, touch points simultaneously touched by three fingers on the screen. However, when a CTP reference signal value (i.e., Baseline) is abnormal or suffers radio frequency interference, for example, a touchscreen of a mobile phone is in contact with a thigh when the mobile phone receives a call waking up signal, during self-calibration of the mobile phone, the mobile phone considers a state in which the touchscreen is in contact with the thigh (that is, there is a conductor) as a normal state, and a state in which the touchscreen is not in contact with the thigh (that is, there is no conductor) as a state in which a touch point is touched all the time. That is, after the touchscreen is woken up and the reference signal value is abnormal, when the touchscreen is moved away from the thigh, the touchscreen may determine that multiple different conductors touch the touchscreen currently, and a quantity of the conductors exceeds an upper limit that can be detected by the touchscreen. Therefore, when a user operates a terminal to answer a call or refuse a call, the terminal does not obtain a touch point that is touched by the user on a touchscreen. As a result, the touchscreen is invalid when being woken up, the user cannot perform a touch operation on the screen, that is, a screen freezing phenomenon occurs, and user experience is poor.